Hi everyone,
I need your help calculating the estimated effect size for a non-inferiority hypothesis.
I have calculated de sample size for an efficacy hypothesis of a binary outcome using
power twoproportions 0.25, test(chi2) rrisk(0.85) power (0.90)

Based on that the sample size should be 2655 in each arm.
Now I have the secondary hypothesis that is a non-inferiority. I need to calculate the possible effect size on a different binary outcome considering that sample size (with a margin of 0)
Is it ok to do the following- considering a prevalence in the control group of 10% and a total sample size of 5310:

power twoproportions 0.10, test(chi2) effect(rrisk) power (0.90) n(5310)

I would appreciate any help possible.
Thank you very much,
Nicole